I use Yahoo mail and since a few weeks it is no longer possible to send mail where I past text All the buttons under the new mail at the bottom will disappear, and the complete image on the screen will move to the left. What is left is a blank field with text.This happens by create, forward and answer a mail.As long as I don't past text everything is ok,but I need to paste most of the time several lines of text.
Disable pop up blocker wont help.
Other browsers (I installed Firefox an Chrome special to test and remove them after testing, even Edge works fine))works fine with yahoo and it is the only webmail that the problem have.
Is there anything I can do to resolve this problem ore the problem is related to yahoo?

See if it works right for you in incognito mode. If so, maybe an extension is the cause.
You can also try clearing your browsing data in Advanced Settings.
I'm on Slimjet 22.0.4.0, no problem with Yahoo mail.

There has to be something different then between regular & incognito mode. Not sure what though, adblocker maybe?

I wrote in my question disable pop blocker, but that should of course be ad blocker.
Any more suggestions?

If you're on Windows, you can run your antivirus/malware scans, even though that's unlikely to be the problem. I still suspect something in your browsing data. Maybe try running a history eraser extension like One Click Cleaner with all items checked down to & including localStorage. Reboot after making changes:

Which adblocker are you using? If the Slimjet one, disable it in Advanced Settings. I still wonder if the adblocker might be the problem anyway. Try Yahoo mail with adblocker disabled in Settings. If it still doesn't work, run One Click then.

The adblocker in slimjet is not the problem.If full disabled the problem still exist.Only in the incognito mode it works fine.
Reed my comment about one click cleaner! Is there no other cleaner available?that works fine on slimjet? I have Ccleaner but that's a disaster to use in slimjet.